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A power-balance model, with radiation losses from impurities and neutrals, gives a unified description of the density limit (DL) of the stellarator, the L-mode tokamak, and the reversed field pinch (RFP). The model predicts a Sudo-like scaling for the stellarator, a Greenwald-like scaling, , for the RFP and the ohmic tokamak, a mixed scaling, , for the additionally heated L-mode tokamak. In a previous paper (Zanca et al 2017 Nucl. Fusion 57 056010) the model was compared with ohmic tokamak, RFP and stellarator experiments. Here, we address the issue of the DL dependence on heating power in the L-mode tokamak. Experimental data from high-density disrupted L-mode discharges performed at JET, as well as in other machines, are taken as a term of comparison. The model fits the observed maximum densities better than the pure Greenwald limit.

The 2014–2016 JET results are reviewed in the light of their significance for optimising the ITER research plan for the active and non-active operation. More than 60 h of plasma operation with ITER first wall materials successfully took place since its installation in 2011. New multi-machine scaling of the type I-ELM divertor energy flux density to ITER is supported by first principle modelling. ITER relevant disruption experiments and first principle modelling are reported with a set of three disruption mitigation valves mimicking the ITER setup. Insights of the L–H power threshold in Deuterium and Hydrogen are given, stressing the importance of the magnetic configurations and the recent measurements of fine-scale structures in the edge radial electric. Dimensionless scans of the core and pedestal confinement provide new information to elucidate the importance of the first wall material on the fusion performance. H-mode plasmas at ITER triangularity (H  =  1 at βN ~ 1.8 and n/nGW ~ 0.6) have been sustained at 2 MA during 5 s. The ITER neutronics codes have been validated on high performance experiments. Prospects for the coming D–T campaign and 14 MeV neutron calibration strategy are reviewed.

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Since the installation of an ITER-like wall, the JET programme has focused on the consolidation of ITER design choices and the preparation for ITER operation, with a specific emphasis given to the bulk tungsten melt experiment, which has been crucial for the final decision on the material choice for the day-one tungsten divertor in ITER. Integrated scenarios have been progressed with the re-establishment of long-pulse, high-confinement H-modes by optimizing the magnetic configuration and the use of ICRH to avoid tungsten impurity accumulation. Stationary discharges with detached divertor conditions and small edge localized modes have been demonstrated by nitrogen seeding. The differences in confinement and pedestal behaviour before and after the ITER-like wall installation have been better characterized towards the development of high fusion yield scenarios in DT. Post-mortem analyses of the plasma-facing components have confirmed the previously reported low fuel retention obtained by gas balance and shown that the pattern of deposition within the divertor has changed significantly with respect to the JET carbon wall campaigns due to the absence of thermally activated chemical erosion of beryllium in contrast to carbon. Transport to remote areas is almost absent and two orders of magnitude less material is found in the divertor.

The genus Maoricicada Dugdale, 1972 includes 19 taxa, of which 15 are described here. Ten from the South Island mountains are described as new: M. alticola, M. clamitans, M. mangu gourlayi, M. m. multicostata, M. m. celer, M. nigra [rigida, M. otagoensis otagoensis, M. o. maceweni, M. phaeoptera, and M. tenuis. The distributions of most taxa are mapped, their songs are represented by sonograms, and their known periods of emergence are recorded. Evidence of hybridisation is unknown. Most species are characteristic of open, unforested sites; M. nigra nigra and M. oromelaena occur close to the summer snowline, a zone not known to be inhabited by cicadas elsewhere in the world.295

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At Enderby Island, a deposit of till, here named the Enderby Formation, locally separated into upper and lower members by lenses of laminated lake siltstone, overlies a sequence of flat-lying basalt flows, perhaps benched by ,the sea during an interglacial period of high sea level. Except on the coast these deposits are blanketed by zonal peat, 3 m thick, which contains the record of post-glacial vegetation.The Lower Till was deposited by the extended glacier that spread out from Laurie Harbour, at the head of Port Ross, flowing from the higher parts of the Ross Volcano when sea level was low, presumably during an early stadial of the last (or Otiran) glacial stage.The Laminated Siltstone (5 m), deposited in a pro-glacial meltwater lake dammed by moraine during a lateral swing or temporary retreat of the glacier, is injected by curious carrot-shaped structures of till, each apparently emplaced by the rapid sinking of a ma.'''11 of rock-laden iceberg which penetrated the unconsolidated silts to depths of almost two metres. The emplacement of such "till carrots" was contemporary with deposition of the silt. The ice re-advanced to deposit an Upper Till Member over the underlying members, locally deforming them and picking up siltstone clasts.The Laminated Siltstone and a clast of siltstone from the Upper Till contain pollen 'and spores indicating a cold-climate vegetation of dominant Compositae with associated herbs, grass, sedge and scrub (Coprosma, Dracophyllum, and Myrsine) but lacking Metrosideros and other trees of the present Auckland Island vegetation.The till members may represent two stadials of the last glaciation and the siltstone an interstadial between them, or they may merely represent fluctuations of minor significance.The blanket peat overlying the till sequence has three members, a lower peat with tree stumps, a middle sandy peat containing angular sand 'and subangular basalt clasts (up to 45 cm through), and an upper peat with scattered well-rounded basalt pebbles, identified as seal gastroliths. The sandy peat is tentatively attributed to the influence of blown sand advancing inland when the post-glacial sea (also represented by an elevated beach) first 'approached its maximum level.Four zones in the peat can be defined from pollen analysis. In Zone 1, woody elements (e.g. Myrsine, Coprosma) and Compositae are abundant, with sedge and grass, and at the top of the zone rooted stumps of Dracophyllum (underrepresented by pollen) gave a HC age of 8630 ± 80 yr BP. In Zone 2, Anisotome pollen increases, Myrsine, Coprosma and Olearia-type pollen grains decrease, Dracophyllum enters with various herbs, and persistent grass is dominant over sedge. In Zone 3, Metrosideros pollen is relatively common.Tillaea and sedges rise steeply as grass declines but Myrsine, Coprosma and Dracophyllum decrease. In Zone 4, grass increases once more (with Myosotis and Myrsine) while Bulbinella, Anisotome and woody shrubs decrease.The Metrosideros phase in Zone 3 (reflecting a warm interval from ca. 6000 to 3000 yr ...